Alarm-train limit mechanism for single-spring alarm clocks



Jan. 16, 1951 P. H. MORGANSON 2,538,161

ALARM-TRAIN LIMIT MECHANISM FOR SINGLE SPRING ALARM CLOCKS 2 Sheets-Shee t 1 Filed March 4, 1948 Jan. 16, 1951 P. H. MORGANSON 2,538,161

, ALARM-TRAIN LIMIT MECHANISM FOR SINGLE SPRING ALARM CLOCKS Filed March 4, 1948 2 Sheet-Sheet 2 yen for Patented Jan. 16, 1951 ALARM-TRAIN LIMIT MECHANISM FOR SINGLE SPRING ALARM CLOCKS Peter H. Morganson, Winsted, Conn assignor to The William L. Gilbert Clock Corporation, Winsted, Conn a corporation of Connecticut Application March 4, 1948, Serial No. 13,006

3 Claims. 1 The present invention relates in general to time-pieces and more especially to that .class of clocks having an audible signal whichisdriven from the same spring-motor which drives the time-train of the clock.

An object of the invention is to provide a superior automatic limit-mechanism for the alarm-train of an audible-signal-clock.

A-further object of the invention is to provide an audible-signal clock of the type having an alarm-train driven from the same spring-motor which drives the time-train, with superior means for automatically limiting the operation of the alarm-train so as not to run down the springmotor ,to the detriment of the time-train.

With the above and other objects in view, as will-appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certainmodes of carrying out the present invention are shown for illustrative purposes:

Fig. l is 'a rear elevation of an alarm-clock movement embodying the alarm-train limitmeans of this invention, a portion of the rear movement-plate being broken away to show details of the time-train and alarm-train;

Fig. 2 is a bottom plan view of the alarm-clock movement of Fig. 1;

Fig. 3 is a broken detail elevation in section of the mainspring and main gears of the time-train and alarm-train on section line 3-3 of Fig. 1, including the improved alarm-train limit-means of this invention;

Fig. i is a sectional view of the mainspring and mainspring-barrel assembly on the line 44 of Fig. 3;

Fig. 5 is a perspective view of the spider of the improved alarm-train limit-means of this invention;

Fig. 6 is a perspective view of the main gear of the alarm-train showing the spring-leaf projecting from the rear face thereof; and

Fig. '7 is a fragmentary perspective View of a portion of the rear movement-plate showing a pair of stops bent forwardly from the rear face thereof.

The particular audible-signal clock shown and described herein for illustrating the present invention includes a rear movement-plate l0 and a front movement-plate II, the rear movementplate and front movement-plate being secured together in parallel spaced-apart relationship by means of suitable pillars [2. In the present embodiment, the front and rear movementplates are substantially rectangular and hence four pillars [2 are provided, one at each corner respectively .of the movement-plates, as shown in Fig. .1. .Mounted between the front and rear movement-plates is a mainor winding-arbor t3, the forward end of which is reduced in cross section .to provide a trunnion 14 having a bearing .in anaperture .of the front movement-plate ii. The rearendof the winding-arbor is similarly reduced in cross section to provide a stemportion iii which projects through a bearingaperture in the rear movement-plate. The spiral driving-spring of the timepiece, hereinafter referred to as the Inainspring, is indicatedat 116, its innerend being secured over a hook 1 1 of the winding-arbor 13-, .as indicated especially well in Figs. 3 and 4, for driving the latter, as hereinafter described.

The said spiral mainspring 16 is housed within a spring-barrel l8, having an ,apertured bottom which comprises the main gear-wheel IQ of a time-train, indicated generally by the gears .20, the gear-teeth 2! ofthe main-wheel l9. extending laterally and circum'ferentially beyond the cylindrical wall of the spring-barrel I B. Thesaid springebarrel 13 is rigidly attached to .the main gear-wheel l9 by .a plurality of integral attaching-fingers .lBa extending through the said gear-wheel and rivetedover against the opposite face thereof. The main ear-wheel 19 of the spring-barrel, referred toherinafteras the first main-wheel, is provided with a central aperture for accommodating the. collar 22 of a flanged bushing 23 which is mounted with freedom for rotationupon the forward portion of the ,windingarbor J3 intermediate the front movement-plate II .and .the underside of the spring-barrel. As

shownespecially well in Fig. 3, the first mainwheel 19 of the spring-barrel is engaged against the .rear face of a flange 24 pf the bushing 23 andisfirmly secured thereto by peening or otherwise fianging the collar-portion 22 .of the bushingover the .rearfaceof the first main-wheel [9. The outerend of the mainspring i6 is adapted to engage over .a hook 25 formed inwardly in the cylindrical wall of the spring-barrel, for driving .the first main-wheel of the time-train of the clock.

Between the .plane .of the .rear edge of the spring-barreland .the forward face ,of the rear movement-plate is a stepped bushing'ZE which is adapted .to make a tight friction .fit .on the .corresponding portion of the winding-arbor, the friction fit being enhanced by longitudinal =rib- 3 bing, knurling or the like, formed thereon. Mounted tightly on the smaller hub 21 of the stepped bushing 26 is the main gear-wheel 28 of the hereinafter-described alarm-train, the gear 28 being referred to hereinafter as the second niainwvheel. The latter is substantially equal in diameter to the diameter of the first main wheel [9 of the time-train and is fixedly secured to the hub 21 of the stepped bushing 26 by peening or flanging the inner end thereof over the corresponding face of the second main-wheel 28. Referring particularly to Figs. 3 and 6, the second main-wheel 28 is provided with a projection 253 comprising an arcuate resilient leaf which is substantially concentric with the second main-wheel and is struck up therefrom to provide a shoulder so at its free end, the resilient leaf.

constituting the actuator of the automatic alarmtrain limit-means of this invention.

Mounted on the second hub 3| of the stepped bushing 26 is a spider 32 which is a second element of the alarm-train limit-means, the spider 32 being freely rotatable on the hub 3! of the stepped bushing but held snugly between the rear face of the second main-wheel 23 and the forward face of the third hub 33 of the bushing 26. Referring especially to Fig. 5, the spider 32 will be seen to comprise a substantially-flat ring-shaped member having a finger 34 projecting radially from the outer periphery thereof; and three substantially equally-spaced tongues 35 projecting inwardly radially from the inner periphery of the ring, the inner ends 36 of the tongues constituting three points on the circumference of a circle, the diameter of which corresponds to or is slightly greater than the diameter of the second hub 3| of the stepped bushing so that the spider may revolve freely thereon.

From the foregoing description, it will be manifest that the first main-wheel IQ of the time-train is mounted for rotation freely upon the Winding.

arbor and is connected to the outer end of the mainsp-ring by means of the hook 25 of the springbarrel, whereby the unwinding of the outer end of the mainspring drives the first main-wheel of the time-train. The second main-wheel 28 of the alarm-train is, however, through the intervention of the stepped bushing 26, fixedly secured to the rear end of the winding-arbor I3, and inasmuch as the latter is connected to the inner end of the mainspring by means of the hook H, the unwinding of the inner end of the mainspring serves to drive the second mainwheel 28 of the alarm-train. The mainspring It thus constitutes a double-end driving-spring. Moreover, since the spider 32 is held snugly between the second mainwheel 28 and the rear hub 33 of the stepped bushing, the spider 3| will rotate with the mainwheel of the alarm-train unless positively restrained. More especially, in view of the fact that the resilient leaf or actuator 29 of the second mainwheel 28 is substantially opposite and hence adapted to project rearwardly into the annular space between the hub 31 of the stepped bushing 26 and the inner periphery of the spider 32, as shown especially well in Fig. 1, as the second main-wheel 28 is rotated in a clockwise direction, its actuator 29 will move against the forward face of one of the tongues 35 of the spider and engage the latter with sufiicient frictional force to pick up the spider and rotate the latter with the second main-wheel. v

The concurrent rotation of the spider and second main-wheel 28 is limited, however, by means of suitable stop-lugs 31 formed down or forwardly 4 from the rear movement-plate and constituting elements of the alarm-train limit-means. Referring particularly to Figs. 1 and '7, the aforesaid stop-lugs are located on opposite sides respectively of the aperture which accommodates the reduced stem-portion iii of the winding-arbor, the stoplugs being spaced apart transversely a distance slightly greater than the diameter of the spider and such as to intersect the path of movement of its finger 3 3. Moreover, the free ends 38 of the stop-lugs lie in a transverse plane below the transverse diameter of the spider a distance corresponding substantially to one-half the width of the finger (i i of the spider. As shown especially well in Figs. 1 and 2, the stop-lugs of the rear movement-plate are adapted thus to positively limit the degree of rotation of the spider for movement thereof in both a clockwise and counterclockwise direction, in the manner hereinafter ,described.

Referring especially to Fig. 1, when the wind ing-arbor i3 is rotated in a clockwise direction to wind up the mainspring 32, the spider will be picked up by the resilient actuator 29 of the second main-Wheel 28 due to frictional engagement of the actuator 29 therewith, and rotated with the second main-wheel 28 in a clockwise direction until the radially-projecting finger 34 of the spider is brought into engagement with the stoplug 31 at the right-hand side of the movementplate, whereupon further rotation of the spider with the second main-wheel is prevented. However, the second main-wheel is permitted to con- I tinue to rotate in a clockwise direction, its resilient leaf 29 flexing downwardly sufliciently to move successively beneath the inwardly-projectin tongues 35 of the positively held spider and to clear the latter with a slight clicking sound.

It will be appreciated that inasmuch as the second main-wheel 28 of the alarm-train is rotated while the main-spring is being wound, suitable escapement-means must be provided in the alarm-train to disconnect the latter from the alarm-hammer 39 which normally is held from operating by the alarm-control finger 40 of the alarm-control arm M, in a well known manner.

To this end, the second main-wheel 28 meshes with a pinion d2 of the alarm-train, which pin ion is secured to the lower end of an arbor 43 bearing at its opposite ends in the front and rear movement-plates of the timepiece. Mounted on the arbor adjacent the forward end thereof, is an alarm-train ratchet mechanism, indicated generally at id, and comprising a ratchet-wheel secured to the arbor; and a pawl t5, the latter being pivotally mounted on the front face of an idler-gear 4'! of the alarm-train rotatable freely on the forward end of the arbor. As is characteristic of the ratchetwhee1-and-pawl as sembly, the pawl 15 disconnects the idler-gear M from the ratchet-wheel when the latter is rotated in a counterclockwise direction, but serves to connect the idler-gear all thereto when the ratchet-wheel is rotated in a clockwise direction. Thus, when the second main-wheel 28 is rotated clockwise, as occurs when the mainspring is being Wound, the pinion 12 and hence the ratchetwheel are freely rotatable counterclockwise, even though the hammer 39 of the alarm-train is held locked by the alarm-control arm 4|. However, after the mainspring has been wound up and the alarm-control arm 4'! is moved into the position shown in Fig. l to release the hammer 39, the force exerted by the inner end of the wound mainspring on the winding-arbor rotates the second mainvvhe'e'l counterclockwise, thus rotating the 'p'inion'42 and the ratchet-wheel clckwise,"-whereupon the pawl is picked up and rotated in "a "similar direction, thereby transmitting-clockwise rotation to the idler-gear -41 of the alarm-train, whereby the 'verge-wheel48 and hammer 39 of the alarmare operated.

Assuming now that priorto actuation ofthe alarm-control-arm d l to release the hammer-arm 39the spider of the alarmtrain-limit-means has been rotatedclockwise (bywvinding up the mainspring) until its finger 34 -has -been brought up against the right-hand stop-"lug 3'1- of the-rear movement-plate, in the manner here'inabove described. Then, upon release of the hammer '39, the alarm-train will be unlocked, whereupon the second main-wheel 18 of the alarm-train-will be rotated counterclockwise by the unwinding of the inner end of the mainspring. Almost immediately, the spider will be rotated with the second imam-wheel 7:28 in 1a counterclockwise direction by engagement of thetshoulder-3fl 'of the resilient actuator 29 with'one of the three radial tongues 35 of the spider, whereby the finger 33 of the spider will be rotated counterclockwise from the right-hand stop-lug of the movementplate into engagement with the left-hand stoplug, whereupon the spider is positively held from further rotation in a counterclockwise direction. Consequently, the second main gear-wheel 28 is also looked from further rotation in a counterclockwise direction, and actuation of the alarmtrain ceases. With the second main gear-wheel 28 held against further counterclockwise rotation as just described, the inner end of the mainspring is positively held so as to prevent complete unwinding of the mainspring, the total time-interval for actuation of the alarm-train corresponding substantially to 180 of rotation of the second main-wheel 28, or substantially onehalf of one complete rotation of the inner end of the mainspring. The outer end of the latter continues to unwind to drive the time-train of the clock for a relatively-long period thereafter. Although in the present embodiment two stoplugs are provided on the rear movement-plate to limit the rotation of the spider to substantially 180, it will be understood that one stoplug may be disposed with relation to the second stop-lug so as to permit the spider to rotate through substantially anynumber of degrees between 0 and 360; and that one stop-lug only will suffice for limiting the rotation of the spider to substantially one complete revolution.

On rewinding the mainspring, clockwise rotation of the second main-wheel 28 will pick up the spider 32 through frictional engagement of the resilient leaf or actuator 2%) of the second main-wheel 28 with the tongues 35 of the spider, as described above, to rotate the latter clockwise until its finger 34 is again in engagement with the right-hand stop-lug of the rear movementplate. Further clockwise rotation of the second main-wheel is accompanied by a clicking sound, as its resilient leaf 29 clears the tongues of the spider.

By means of the clock mechanism described above and more especially the stop-means of the alarm-train, both a time-train and an alarmtrain may be driven from a single spring-motor without the possibility of the alarm-train utilizing more power of the wound mainspring than is necessary to effectively sound an alarm.

The invention may be carried out in other specific ways than those herein set forth without departing "from the spirit-and --essenti-al charac teristicsofthe invention,=-andthe present embodiments are, therefore, to be -considered in all-respects as illustrative and -not restrictive, and all changes coming within the meaning and equivalency-range of the appended claims are intended to be embraced therein.

1 claim:

1. An audible-signal clock, including in combination: -a main-arbor; a first main-wheel mounted on said main-arbor and rotatable with respect thereto; a double-ended driving-spring having its inner end operatively connected "to-the said main-arborand its opposite end operatively connected to the said first main-wheel; a second main-wheel operatively connected to the said main-arborya time-train driven by the said "first main-wheel; an'alarm-train driven by the said second *main-wheel; and automatic=means to: limit-the degree of rotation of said secondmainwheel by said arbordn-a direction to unwind the inner end ofsaid driving-spring, including 'a rotatable 'member supported by said main-arbor and rotatable =freely"with respect to said second'mainwheel, 'saidrotatable member comprising a ringmember having a finger projecting outwardly radiallytherefrom and a plurality of inwardlyproj ec'tingsubstantially-radial tongues, the inner free ends of which are arranged to engage circumferentially with said main arbor, a single actuator carried by said second main-wheel arranged to coact with one of the said tongues of said ring-member to positively rotate the latter concurrently with said second main-wheel when the latter is rotated by said main-arbor in a direction to unwind the inner end of said drivingspring, and a fixed element arranged to extend into the path of rotation of the said finger of said ring-member to stop said ring-member and the concurrently rotating second main-wheel thereby to limit the operation of said alarm-train.

2. An audible-signal clock, including in combination: a main-arbor; a first main-wheel mounted on said main-arbor and rotatable with respect thereto; a double-ended driving-spring having its inner end operatively connected to the said main-arbor and its opposite end operatively connected to the said first main-wheel; a second main-wheeloperatively connected to the said main-arbor; a time-train driven by the said first main-wheel; an alarm-train driven by the said second main-wheel; and automatic-means to limit the degree of rotation of said second mainwheel by said arbor in a direction to unwind the inner end of said driving-spring, including a rotatable-member supported by said main-arbor and rotatable, freely with respect to said second main-wheel, said rotatable-member comprising a ring-member having a finger projecting outwardly radially therefrom and a plurality of inwardly-projecting substantially-radial tongues, the inner free ends of which are arranged to engage circumferentially with said main arbor, a single resilient leaf projecting from said second mainwheel arranged to coact with one of the said tongues of said ring-member to positively rotate the latter concurrently with the rotation of said second main-wheel when the latter is rotated by said main-arbor in a direction to unwind the inner end of said driving-spring; and a stop-lug arranged to extend into the path of rotation of said finger to stop said ring-member and the concurrently rotating second main-wheel thereby to limit the operation of said alarm-train.

7 53. An audible-signal clock, including in combination: a main-arbor; a first main-whee1 mounted on said main-arbor and rotatable with respect thereto; a double-ended driving-spring having its inner end operatively connected to the said main-arbor and its opposite end operatively connected to the said first main-wheel; a second main-wheel operatively connected to the said main-arbor; a time-train driven by the said first main-wheel; an alarm-train driven by the said second main-wheel; automatic-means to limit the degree of rotation of said second main-wheel by said arbor in a direction to unwind the inner end of said driving-spring, including a rotatablemember supported by said main-arbor and rotatable freely with respect to said second mainwheel, said rotatable-member comprising a ringmember having a finger projecting outwardly radially therefrom and a plurality of inwardlyprojecting substantially-radial tongues, the inner free ends of which are arranged to engage circumferentially with said main arbor, a resilient projection on said second main-wheel arranged to coact with one of the said tongues of said ringmember to positively rotate the latter concurrently with said second main-wheel when the latter is rotated by said main-arbor in a direction to unwind the inner end of said mainspring and to frictionally rotate said ring-member concurrently with the rotation of said second mainwheel when the latter is rotated by said mainarbor in a direction to wind up said drivingspring, and a stop-lug arranged to extend into the path of rotation of the finger of said ringmemberto stop said rotatable-member and the concurrently rotating second main-wheel thereby to limit the operation of said alarm-train; and ratchetmechanism in said alarm-train arranged to disconnect said second main-wheel therefrom when said second main-wheel is rotatedby said main-arbor in a direction to wind up said mainspring and to connect said second main-wheel to said alarm-train when said second main-wheel is rotated by said arbor in a direction to unwind the inner end of said mainspring.

PETER H. MORGANSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 188,865 Davies et a1 Mar. 27, 1877 2,108,776 McNicoll Feb. 15, 1938 2,467,925 Andrews Apr. 19, 1949 

